Stepped grate for an agricultural combine

ABSTRACT

A grate for an agricultural combine includes curved grate segments, each of which include mounting holes in at least one end segment. To provide a threshing grate, the end segments of the grate segments are offset to provide a “step”, or discontinuity in the radius of the assembled grate, which improves the threshing efficiency of the combine. The step can be provided by offsetting mounting holes between adjacent grate segments, and securing the grates to a frame member.

FIELD OF THE INVENTION

This invention relates generally to rotary combines. It relatesparticularly to an improved grate system in a rotary combine for moreeffectively separating grain and MOG (material other than grain) afterit passes through the combine's threshing concave.

BACKGROUND OF THE INVENTION

Agricultural combines for harvesting and threshing of crop materials arewell known in the art. Typically, agricultural combines includes a cropharvesting apparatus which reaps planted grain stalks, and an infeedmechanism arranged at the forward end of the combine to feed the grainstalks to a separating apparatus. The separating apparatus acts on thecrop materials to thresh and separate grain from material other thangrain (MOG).

Threshing takes place between an elongated rotor assembly and acylindrical housing which encases the rotor assembly. The rotor assemblyincludes a cylindrical rotor drum having a plurality of threshingelements radiating from it. The threshing elements are mounted on theouter skin of the rotor, and may take the form of rasp bars which canbe, for example, arranged in a helical path around the rotor, fastenedto the outer skin of the rotor on suitably configured brackets.

The separating apparatus typically includes an axially elongated piercedcasing or cage surrounding a rotor. Between the upstream and downstreamends of the separating apparatus, the crop materials are repeatedlythreshed as the cage spirals around the large diameter rotor. Suitableinstrumentalities on the rotor cooperate with an axially elongatedthreshing section on the lower portion of the casing to thresh the cropmaterials such that most of the grain will be separated and propelleddownwardly through the threshing section. The threshing section of thecasing or cage is comprised, at least in part, by a series ofside-by-side semi-cylindrical perforated concaves and semi-cylindricalgrates. The rotor cooperates with the semicylindrical concaves andsemicylindrical grates to thresh the crop materials such that most ofthe grain will be separated and propelled downwardly through theconcaves and grates.

During this process, the primary separation of grain from MOG isprovided in the concave area. Here, the crop materials including bothgrain and MOG are compressed, and then rotated around the cage area,such that the easily-removed grain is threshed from the MOG. The cropmaterial mix progresses to the semicylindrical grate area, whereadditional threshing is performed to separate additional remaining grainfrom MOG.

While prior art axial combines have been largely successful inseparating grain, a significant portion of grain remains in the crop mixafter the grating process. There remains a need, therefore, for animproved threshing system for separating grain from other material.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the present invention provides a grate assembly for anagricultural combine. The grate assembly includes a first and a secondgrate member, each grate member having first and second ends and firstand second curved sides. At least one of the end members of each gratemember includes a mounting hole sized and dimensioned to receive acoupling element. The mounting hole in the first grate member is offsetfrom the mounting hole in the second grate member such that, when thegrate members are aligned and a coupling member is positioned betweenthe mounting holes, the adjacent members provide a substantiallysemi-circular grate assembly in which the radius is discontinuous,forming a step.

In another aspect of the invention, a separating grate for anagricultural combine is provided. The separating grate includes a framehaving first and second offset end members, first and secondsemi-circular side members extending between the offset end members, anda longitudinally-extending mounting bracket extending between the firstand second semi-circular side members. The longitudinally-extendingmounting bracket includes at least one mounting aperture. The separatinggrate further includes a first and a second grate member sized anddimensioned to be received in the frame between the first end member andthe longitudinally-extending mounting bracket. The grate members eachinclude first and second ends and first and second curved sides. Atleast one of the end members of each of the first and second gratemember includes a mounting aperture for mounting the respective gratemember to the longitudinally-extending mounting bracket. The mountingaperture in each of the first and second grate member is offset from thetop of the respective end member by a different selected distance, suchthat when the first and second grate members are positioned in the framemember, the grate assembly includes a radius which is stepped at theinterface between the first and second grate members.

In yet another aspect of the invention, an apparatus for threshing graincomprises a rotor provided in a rotor housing and a separating gratelocated between the rotor and the housing. The separating gratecomprises at least a first and a second curved grate member, each gratemember comprising first and second curved side members extending betweenfirst and second rectangular end members. In the separating grate, atleast one of the end segments of the first grate member abuts at leastone of the end segments of the second grate member to form a gratehaving a radius extending substantially around the rotor. The firstgrate is offset from the second grate at the abutment surface to providea step in the radius of the separating grate at which one of the firstand second grate members is radially closer to the rotor than the otherof the first and second grate members.

These and other aspects of the invention will become apparent from thefollowing description. In the description, reference is made to theaccompanying drawings which form a part hereof, and in which there isshown a preferred embodiment of the invention. Such embodiment does notnecessarily represent the full scope of the invention and reference ismade therefore, to the claims herein for interpreting the scope of theinvention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view, partially broken away, of an agriculturalrotary combine.

FIG. 2 is partial side view of a separating apparatus for a rotarycombine.

FIG. 3 is a perspective view of a rotor assembly and threshing cageconstructed in accordance with the present invention.

FIG. 4 is a perspective view of a frame for constructing the separatinggrate assembly of FIG. 3.

FIG. 5 is a perspective view of a first grate member for receipt in theframe of FIG. 4.

FIG. 6 is a perspective view of a second grate member for receipt in theframe of FIG. 4.

FIG. 7 is a partial close-up view of the separating grate assemblymounted to the rotor as shown in FIG. 3.

FIG. 8 is a rear view of the rotor assembly of FIG. 3 as assembled in acombine.

FIG. 9 is a rear view of a rotor assembly of a typical prior art combinetaken from the same angle as FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the figures and more particularly to FIG. 1, a typicalself-propelled rotary combine 10 in which the grate of the presentinvention can be used is shown. The combine 10 includes a longitudinalor fore-and-aft extending frame 11 that includes a body or housing 12defining an internal open area or space 13 and which is supported onfront drive wheels 14 and steerable rear wheels 16. The combine 10 ispowered by an engine (not shown) and controlled from an operator'sstation 18. A crop harvesting apparatus or header 20 and an infeedmechanism 22 are attached at a forward end of the combine. The infeedmechanism 22 feeds crop materials to a rotor assembly 24 enclosed withinhousing 12.

Referring now to FIG. 2, the rotor assembly 24 threshes and separatesthe crop materials presented into grain and material other than grain(MOG). As shown, the rotor assembly 24 is mounted in the internal area13 defined by housing 12 and comprises an elongated and generallycylindrical member 26 in the form of a rotor casing or cage having arotor 28 mounted for rotation therein and about a fixed axis 30. Betweenthe upstream and downstream ends of the rotor assembly 24, the cropmaterial is threshed repeatedly as it spirals around the single largediameter rotor 28 and grain is permitted to pass through the bored orpierced threshing cage 26. In a conventional manner, suitableinstrumentalities mounted on the periphery of the rotor 28 cooperaterespectively with semicylindrical concaves 34 and semicylindrical grates36 provided along the lower portion of the threshing cage 26 to threshthe crop materials such that most of the grain will be separated andpropelled downwardly through the concaves 34 and grates 36.

Most of the grain drops onto a grain pan 38. The grain is conveyedrearwardly from the pan 38 by an auger mechanism 40 for subsequentcleaning and collection. Straw, tailings and other waste material(collectively, mog) is impelled rearwardly out of the discharge end 32of the rotor assembly 24 where a rotary beater 42 throws the straw andother waste material rearwardly from the combine.

The combine further includes a cleaning system for cleaning chaff,straw, tailings and other foreign material from the grain. As is wellknown, the cleaning system includes a cleaning fan 44, a chaffer sieve46, a grain sieve 48 and a clean grain collector 50. A suitable augermechanism 52 directs clean grain from the collector 50 into a hopper(not shown).

Referring now to FIG. 3 a rotor assembly 24 constructed in accordancewith the present invention is shown. As described above the rotorassembly includes a rotor 28 which is provided in a threshing cageincluding semicircular concaves 34 and a separating grates assembly 36.The rotor 28 includes a plurality of rasps 25 for threshing grain from acrop mat. The semicircular concaves 34 and grates 36 have a radiusgreater than the rotor 28, and surround at least a portion of the rotor28 such that, when the rotor is rotated, crop materials are threshedbetween the rotor 28 and the threshing concaves 34 and grates 36.Referring now specifically to the grate construction, the grate 36comprises a frame 54 in which a plurality of grate members 82 and 84 arecoupled. Referring now also to FIG. 4 the frame 54 comprises first andsecond end segments 56 and 62 and curved rib or side members 57, 58, and59 which extend between the end segments 56 and 62. The end segment 56comprises a mounting bracket for mounting the frame 54 to a rotary caseassembly. Each of the semicircular rib members 58 includes a pluralityof downwardly extending mounting tabs 80 including apertures formounting the frame 54 to a rotary case assembly. A longitudinallyextending bracket member 64 extends between pairs of adjacentsemicircular rib members 57 and 58 and 58 and 59, respectively, andincludes downwardly extending tabs 65 including apertures 67 forcoupling the grate members 82 and 84 in the frame 54 as described below.Although three side members 57, 58, and 59 are shown, the number of sidemembers provided in the frame can vary depending on the number of gratemembers used in the threshing operation.

Referring now to FIGS. 5 and 6, grate members 82 and 84, which are sizedand dimensioned to be received in the frame 54 are shown. Each of thegrate members 82 and 84 include a first end member 66, a second endmember 70, and substantially parallel curved side member 74 and 76extending between the end members 66 and 70. The radius of curvature ofthe side members is substantially equivalent to that of the side members57, 58, and 59 of the frame 54 described above. Between the end membersand side members a grate is formed by a combination of parallel,longitudinally extending bar members 72 and transversely extending ribmember 68. The bar members 72 extend between the end members 66 and 70,and are substantially parallel to the side members 74 and 76. The ribmembers 68 extend across the respective grate member from side member 74to side member 76. Each of the rib members 68 and bar members 72 aresubstantially evenly spaced to provide a grid or grate. While a grid orgrate constructed of individual crossed members is shown, various othermethods of producing a grate, including piercing a plurality ofapertures in a plate, can also be used.

Referring still to FIGS. 5 and 6, the end members 66 and 70 of each ofthe grate members 82 and 84 including mounting apertures 86 and 88,respectively, for mounting the grate members 82 and 84 into the frame 54as shown in FIG. 7. The distance 92 between the top edge of the endsegment 66 of the grate member 82 and the mounting hole 86 is smallerthan the distance 94 between the top of the end segment 66 and themounting hole 88 in the grate member 84. When installed in the frame 54,as shown in FIG. 8, the difference in location between the mountingholes causes a “step” to be provided in the radius between the adjacentgrate members 82 and 84.

Referring now to FIG. 7, as described above, the grate members 82 and 84are shown coupled to the frame member 54 to form a separating grateassembly 36. The first grate member 82 is shown mounted between ribmembers 57 and 59, and includes mounting apertures 86 which are providedat a distance 92 from the top of the end member. The second grate member84 is provided between rib members 59 and 58 (FIG. 4) and includes amounting aperture 88 which is offset at the second distance 94 andwhich, therefore provides a “step” in the radius of the assembled grate,as shown below.

Referring now to FIGS. 8 and 9 a rear view of the rotor assembly gratesillustrating the relative position of 82 and 84 as provided in the grateassembly 32 is shown for each of a typically prior art assembly (FIG. 9)and an assembly constructed in accordance with the present invention.Referring first to FIG. 9, in typical prior art assemblies, theseparating grate is radically offset from and substantially equidistantto the rotor 28. Referring not to FIG. 8, in the separating grate 36constructed in accordance with the present invention, a discontinuity inthe radial distance from the rotor to the grate is produced as a “step”.Here, on the left hand side, the grate member 82 follows a radius ofcurvature substantially equidistant from the rotor 28. On the right handside, the grate member 84 is offset, such that the discontinuity or“step” is formed. At the step, the distance between the rotor 28 and thegrate assembly 36 is decreased, such that the grate member 84 is closerto the rotor 28 then the grate member 82.

While the invention has been described as providing a single step, itwill be apparent that grates having a plurality of steps could beconstructed in a similar manner. Moreover, the size of the steps can beeasily varied by changing the reparation distance between the grates.

It should be understood that the methods and apparatuses described aboveare only exemplary and do not limit the scope of the invention, and thatvarious modifications could be made by those skilled in the art thatwould fall under the scope of the invention. To apprise the public ofthe scope of this invention, the following claims are made:

1. A grate for an agricultural combine comprising: a frame includingfirst and second offset end members and first and second semi-circularside members extending between the offset end members; alongitudinally-extending mounting bracket extending between the firstand second semi-circular side members at a position between the firstand second end members, the longitudinally-extending mounting bracketincluding at least one mounting aperture; a first grate member includingfirst and second ends and first and second curved sides and sized anddimensioned to be received in the frame between the first end member andthe longitudinally-extending mounting bracket, at least one of the endmembers of the first grate member including a mounting aperture formounting the first grate member to the longitudinally-extending mountingbracket, the mounting aperture being offset from the top of therespective end member of the first grate by a first selected distance;and a second grate member including first and second ends and first andsecond curved sides and sized and dimensioned to be received in theframe between the second end member and the longitudinally-extendingmounting bracket, at least one of the end members of the second gratemember including a mounting aperture for mounting the second gratemember to the longitudinally-extending mounting bracket, the mountingaperture being offset from the top of the respective end member of thesecond grate by a second selected distance; wherein, when the first andsecond grate members are positioned in the frame member, the first gratemember is stepped upward a distance from the second grate member.
 2. Thegrate as defined in claim 1, wherein the end segment of each of thefirst and second grate members includes a mounting tab extending awayfrom the grate member, the mounting tab comprising the mounting aperturefor receiving the fastener.
 3. The grate as defined in claim 1, whereinthe frame comprises a plurality of longitudinally-extending mountingbrackets spaced along the side members and between the first and secondends of the frames, and a plurality of grate members sized anddimensioned to be positioned between adjacent pairs oflongitudinally-extending mounting brackets.
 4. The grate as defined inclaim 1, wherein the end segments of the first and second frame membersare substantially rectangular.
 5. The grate as defined in claim 1,wherein the first selected distance is different from the secondselected distance.
 6. The grate as defined in claim 1, wherein the firstand second grate members each comprise a plurality of apertures.
 7. Thegrate as defined in claim 1, wherein the first and second grate memberseach include a plurality of ribs that are substantially parallel to thecurved side segments and a plurality of longitudinally extending barmembers that are substantially parallel to the end segments, the ribsand bar members together forming a grid including a plurality ofapertures.
 8. A grate for an agricultural combine, comprising: acoupling device; a first grate member comprising first and second endsand first and second semi-circular sides, at least one of the endsincluding a mounting hole sized and dimensioned to receive the couplingelement; a second grate member comprising first and second ends andfirst and second semi-circular sides, at least one of the ends includinga mounting hole sized and dimensioned to receive the coupling elementfor coupling the first grate member to the second grate member, themounting hole in the first grate member being longitudinally offset fromthe mounting hole in the second grate member such that, when themounting hole in the first grate member is aligned with the mountinghole in the second grate member, the first grate member is offset fromthe second grate member to form a step.
 9. The grate as defined in claim8, further comprising a frame, the frame including a first and a secondsemi-circular side member coupled between a first and a second endmember, and a bracket extending between the first and second sidemembers between the first and second end members, the bracket includinga mounting aperture for receiving the threaded fasteners.
 10. The grateas defined in claim 8, wherein a space defined between each end member,the side members, and the bracket is sized and dimensioned to receiveone of the first and second grate members.
 11. The grate as defined inclaim 8, wherein each of the grate members comprises a plurality ofapertures.
 12. The grate as defined in claim 8, wherein each of thegrate members comprises a plurality of ribs extending between the firstand second ends and parallel to the sides and a plurality of transversecross members extending from the first side to the second side.
 13. Thegrate as defined in claim 8, further comprising at least one additionalgrate member, the at least one additional grate member including amounting hole in an end segment for coupling the at least one additionalgrate member to an adjacent grate member.
 14. The grate as defined inclaim 8, wherein each of the grate members comprises a pierced plate.15. An apparatus for threshing grain comprising: a rotor provided in arotor housing; a threshing grate located between the rotor and thehousing, the threshing grate comprising at least a first and a secondcurved grate member each grate member comprising first and second curvedside members extending between first and second rectangular end members,at least one of the end segments of the first grate member abutting atleast one of the end segments of the second grate member to form a gratehaving a radius extending substantially around the rotor, the endsegment of each of the first and second grate members including amounting tab extending away from the grate member, the first gratemember being offset from the second grate member at the abutment surfaceto provide a step in the radius of the grate at which one of the firstand second grate members is radially closer to the rotor than the otherof the first and second grate members; and a frame member having firstand second end segments, first and second parallel curved sidesextending between the first and second end segments, and at least onelongitudinally-extending mounting bar extending between the first andsecond parallel curved sides at a location between the first and secondend segments, the area between each of the first and second end segmentsand the longitudinally-extending mounting bar being sized anddimensioned to receive one of the first and second grate members,wherein the longitudinally-extending mounting bar includes includesdownwardly extending tabs including aperatures for coupling the firstgrate member and the second grate member to the frame.
 16. The apparatusas defined in claim 15 wherein the mounting tabs at the first and secondgrate members each comprise a plurality of apertures.
 17. (canceled) 18.The apparatus as defined in claim 157, wherein mounting tabs at the endmembers of each of the first and second grate members includes anaperture for mounting the grate member to the longitudinally extendingmounting bracket.
 19. The grate as defined in claim 1, wherein thelongitudinally-extending mounting bar includes downwardly extending tabseach including the at least one aperture for coupling the first gratemember and the second grate member to the frame.
 20. The grate asdefined in claim 9, wherein the bracket includes downwardly extendingtabs each including the mounting aperture for receiving the threadedfasteners.
 21. The grate as defined in claim 9, wherein the end segmentof each of the first and second grate members includes a mounting tabextending away from the grate member, the mounting tab comprising themounting aperture for receiving the fastener.